This study will analyze the monoclonal immunoglobulins in the serum of patients who have biclonal or triclonal gammopathy. We will ultimately determine if the VH and VL regions of biclonal of triclonal immunoglobulins from the same patient that share idiotypic determinants are identical in primary structure. The combinations of immunoglobulins that will be studied include: IgA(kappa) plus IgG(kappa) of patient GR; IgM (kappa) plus IgA(kappa) plus IgG(kappa) of patient CM; IgGl(kappa) plus IgG2 (kappa) plus IgG2(kappa) of patient Tru; IgM(kappa) plus IgA(kappa) of patient Dun. The N-terminal amino acid sequence of the GR alpha- and gamma-chains is known. We will determine the remainder of the amino acid sequence of the VH regions using cyanogen bromide fragments. The N-terminal sequence of the two GR kappa-chains is known. We will determine the sequence of the remaining amino acids in the VL region from peptides produced by tryptic and chymotryptic digestion. With the CM proteins, we will determine if the three kappa-chains are identical by isoelectric focusing, mapping of iodinated tryptic and chymotryptic peptides and N-terminal amino acid sequence. With the CM mu-, alpha-, and gamma-chains, we will first determine their N-terminal amino acid sequence and if these are identical, determine the sequence of amino acids in the remaining portion of the VH region from peptides produced by cyanogen bromide cleavage and tryptic digestion. With the Tru and Dun proteins, we will first determine if the immunoglobulins from a single individual share identical idiotypic determinants. If the Tru and/or Dun immunoglobulins have a common idiotype, we will proceed as for the CM proteins; analyze the L-chains, N-terminal amino acid sequence of L- and H-chains; determine the sequence of the complete VH regions.